Such as Tetrinet [1] which was novel for its time, being a multiplayer game. Oh, wait. (It even worked in Wine and there was a Gtk Linux port of it called gtetrinet.)
That takes me back! gtetrinet was the first program I reported a security-bug in, which eventually lead to the first Debian security advisory I can take credit for:
[1] https://en.wikipedia.org/wiki/TetriNET